In labeling some articles, it is necessary to grip the articles and accurately hold them in a predetermined orientation. This is necessary, for example, in labeling articles, such as bottles, of an irregular configuration with labels which must be accurately oriented on the article.
One prior art way of accomplishing this labeling function is to guide the article into a lead screw with the lead screw rotating at a speed to advance the article at approximately the same rate as the article conveyor. With this arrangement, the article is retained between the threads of the lead screw by a guide. A top hold-down belt holds the article downwardly against the conveyor.
A primary problem with this prior art construction is that a different setup is required for each different size article to be labeled. For example, the lead screw must be changed each time an article of a different length is to be labeled and the height of the hold-down belt must be adjusted each time articles of different height are to be labeled. These changes take time to accomplish and increase the downtime of the labeling line, as well as requiring additional capital outlay and storage space for the different sizes of screws that are necessary.
This prior art construction has other disadvantages. For example, if the article is a bottle with a cap and the cap is inadvertently left off, the top hold-down belt cannot perform its article capturing function due to the reduced overall height of the article as a result of the absence of the cap. In addition, the loading of articles into the screw requires some special consideration, such as a special input device or a jam input. Finally, with the article held by the lead screw, it is sometimes difficult to provide sufficient room while the article is captured to carry out the labeling function.